Spread spectrum communication device and communication system

ABSTRACT

It is the object of the invention to provide a structure of a novel spectrum spreading communication device which solves the problem with the conventional spectrum spreading communication using Barker codes, etc. and limits the rise of the side-lobe of a correctional signal independently of the order of information codes by use of a code sequence having a code length of at least 14. The spectrum spreading communication device uses a pseudo-noise code having a code length of at least 14 and a self-correlation side-lobe of not greater than 3 as a pseudo-noise code of a direct spreading communication device which uses the pseudo-noise codes whose polarities are inverted so as to deal with also digital information. Thus, even when the pseudo-noise code length is 14 or more, the side-lobe of the correction coefficient can be restricted. Accordingly, the error rate of the spectrum spreading communication device is reduced and the processing gain is improved.

TECHNICAL FIELD

The present invention relates to surface acoustic wave devices andcommunication devices.

BACKGROUND ART

In conventional spread spectrum communication devices using the directspreading method, a Barker code was used as a pseudo noise code asdescribed in 1985 ULTRASONICS SYMPOSIUM proceedings, pp. 145-148, forexample. It is known that this code does not depend on the arrangementof an information code sequence and this code has an auto-correlationside lobe of 1.

The Barker code has been found with the code length of 13 or less. TheBarker code has not been found with a code length exceeding it. In thecase where a processing gain of a code length of at least 14 wasrequired, therefore, a code other than the Barker code, such as thelongest code sequence was used. In these code sequences, however, alarge side lobe rise is caused when the sign of the information code isinverted. In general, therefore, the error rate is increased.

An object of the present invention is to solve the above describedproblem and provide a novel structure of a spread spectrum communicationdevice which uses a code sequence having a code length of at least 14,which does not depend on the arrangement of the information code, andwhich suppresses the side lobe rise of correlation signals.

SUMMARY OF INVENTION

The above described object can be achieved by employing a code sequenceused by the present invention, i.e., a code shown in TABLES 1 through 9as the pseudo noise code for spreading the power density spectrum of aninput signal.

It has been confirmed by calculation conducted by the present inventorsthat the code shown in TABLES 1 through 9 has an auto-correlationcoefficient side lobe of 3 or less. If this code is used, therefore,there is obtained a novel spread spectrum communication device andcommunication system which has a processing gain having anauto-correlation coefficient side lobe of at least 14, which does notdepend on the arrangement of the information code, which suppresses theside lobe rise of the correlation signal, and which makes the error ratesmall. In addition, a surface acoustic wave device utilizing thischaracteristic is obtained.

The present invention relates to a novel code having a processing gainwith a code length of at least 14 and an auto-correlation side lobe of 3or less. The code length is determined in some cases by using harmonicsof the crystal (oscillation frequency in the case here a frequencymultiplier is used). In other cases, the code length is generatedindependently of the clock frequency of the baseband digital circuit.

It is now assumed that the code length is determined by using harmonicsof the crystal. If harmonics are generated by distorting the oscillationwaveform of the clock frequency in order to make harmonic componentslarge, for example, only odd-number components included in harmoniccomponents are typically generated. If its odd-number components areused as the clock of pseudo noise code generator, therefore, a valueobtained by dividing the clock of the pseudo noise code generator by theclock frequency of the baseband digital circuit, i.e., the code lengthis obtained. To be concrete, an odd-numbered code length such as 15, 17,19, . . . is obtained.

In the case where the obtained odd-numbered code length is applied to aspread spectrum communication device, two code lengths are combined andused in some cases. To be concrete, it is a result of multiplication ofodd-numbered code lengths. A value of at least 14 such as 15, 21, 25,27, . . . is used as the code length.

In the case where the code length is generated independently of theclock frequency of the baseband digital circuit, it doesn't matter atall whether the code length is even-numbered or odd-numbered andconsequently values of at least 14, i.e., values 14, 15, 16, 17, . . .are obtained.

In either case, a pseudo noise code formed by a large number ofcombinations in respective code lengths is present. Out of them, thepresent inventors found a novel code which is 3 or less inauto-correlation side lobe and which is effective as the pseudo noisecode used for spreading the power density spectrum of an input signal.The present inventors also found a novel pseudo noise generator capableof executing spreading (or de-spreading) of the power density spectrumof an input signal by using those codes.

The following TABLES 1 through 9 show the pseudo noise code concerningthe present invention.

                  TABLE 1                                                         ______________________________________                                        (n = 14)                                                                                         max. corr. max. corr.                                      number bj          (forward)  (back) dc level                                 ______________________________________                                        202    00000011001010                                                                            2          6      -6                                       332    00000101001100                                                                            2          6      -6                                       404    00000110010100                                                                            2          8      -6                                       405    00000110010101                                                                            2          6      -4                                       410    00000110011010                                                                            2          10     -4                                       470    00000111010110                                                                            2          10     -2                                       665    00001010011001                                                                            2          10     -4                                       691    00001010110011                                                                            2          10     -2                                       811    00001100101011                                                                            2          10     -2                                       821    00001100110101                                                                            2          10     -2                                       1883   00011101011011                                                                            2          10     2                                        2375   00100101000111                                                                            2          10     -2                                       2656   00101001100000                                                                            2          8      -6                                       2767   00101011001111                                                                            2          10     2                                        3232   00110010100000                                                                            2          6      -6                                       3247   00110010101111                                                                            2          10     2                                        3322   00110011111010                                                                            2          10     2                                        4021   00111110110101                                                                            2          10     4                                        4622   01001000001110                                                                            2          10     -4                                       5145   01010000011001                                                                            2          6      -4                                       5251   01010010000011                                                                            2          10     -4                                       5312   01010011000000                                                                            2          6      -6                                       5313   01010011000001                                                                            2          8      -4                                       5327   01010011001111                                                                            2          10     2                                        5535   01010110011111                                                                            2          6      4                                        5728   01011001100000                                                                            2          10     -4                                       5758   01011001111110                                                                            2          10     4                                        6092   01011111001100                                                                            2          10     2                                        6118   01011111100110                                                                            2          10     4                                        6575   01100110101111                                                                            2          10     4                                        6645   01100111110101                                                                            2          6      4                                        6650   01100111111010                                                                            2          10     4                                        6880   01101011100000                                                                            2          10     -2                                       7186   01110000010010                                                                            2          10     -4                                       7989   01111100110101                                                                            2          8      4                                        8090   01111110011010                                                                            2          10     4                                        8293   10000001100101                                                                            2          10     -4                                       8394   10000011001010                                                                            2          8      -4                                       9197   10001111101101                                                                            2          10     4                                        9503   10010100011111                                                                            2          10     2                                        9733   10011000000101                                                                            2          10     -4                                       9738   10011000001010                                                                            2          6      -4                                       9808   10011001010000                                                                            2          10     -4                                       10265  10100000011001                                                                            2          10     -4                                       10291  10100000110011                                                                            2          10     -2                                       10625  10100110000001                                                                            2          10     -4                                       10655  10100110011111                                                                            2          10     4                                        10848  10101001100000                                                                            2          6      -4                                       11056  10101100110000                                                                            2          10     -2                                       11070  10101100111110                                                                            2          8      4                                        11071  10101100111111                                                                            2          6      6                                        11132  10101101111100                                                                            2          10     4                                        11238  10101111100110                                                                            2          6      4                                        11761  10110111110001                                                                            2          10     4                                        12362  11000001001010                                                                            2          10     -4                                       13061  11001100000101                                                                            2          10     -2                                       13136  11001101010000                                                                            2          10     -2                                       13151  11001101011111                                                                            2          6      6                                        13616  11010100110000                                                                            2          10     -2                                       13727  11010110011111                                                                            2          8      6                                        14008  11011010111000                                                                            2          10     2                                        14500  11100010100100                                                                            2          10     -2                                       15562  11110011001010                                                                            2          10     2                                        15572  11110011010100                                                                            2          10     2                                        15692  11110101001100                                                                            2          10     2                                        15718  11110101100110                                                                            2          10     4                                        15913  11111000101001                                                                            2          10     2                                        15973  11111001100101                                                                            2          10     4                                        15978  11111001101010                                                                            2          6      4                                        15979  11111001101011                                                                            2          8      6                                        16051  11111010110011                                                                            2          6      6                                        16181  11111100110101                                                                            2          6      6                                        ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        (n = 15)                                                                                           max. corr.                                                                             max. corr.                                      number bj            (forward)                                                                              (back)  dc level                                ______________________________________                                         202   000000011001010                                                                             3        7       -7                                       332   000000101001100                                                                             3        7       -7                                       345   000000101011001                                                                             3        7       -5                                       394   000000110001010                                                                             3        7       -7                                       404   000000110010100                                                                             3        9       -7                                       405   000000110010101                                                                             3        7       -5                                       410   000000110011010                                                                             3        11      -5                                       618   000001001101010                                                                             3        7       -5                                       652   000001010001100                                                                             3        11      -7                                       664   000001010011000                                                                             3        11      -7                                       665   000001010011001                                                                             3        11      -5                                       678   000001010100110                                                                             3        7       -5                                       691   000001010110011                                                                             3        7       -3                                       710   000001011000110                                                                             3        11      -5                                       718   000001011001110                                                                             3        7       -3                                       808   000001100101000                                                                             3        11      -7                                       809   000001100101001                                                                             3        11      -5                                       810   000001100101010                                                                             3        7       -5                                       811   000001100101011                                                                             3        9       -3                                       821   000001100110101                                                                             3        7       -3                                       922   000001110011010                                                                             3        11      -3                                       1140  000010001110100                                                                             3        11      -5                                       1221  000010011000101                                                                             3        11      -5                                       1299  000010100010011                                                                             3        11      -5                                       1305  000010100011001                                                                             3        11      -5                                       1356  000010101001100                                                                             3        11      -5                                       1380  000010101100100                                                                             3        11      -5                                       1610  000011001001010                                                                             3        11      -5                                       1620  000011001010100                                                                             3        11      -5                                       1642  000011001101010                                                                             3        11      -3                                       1672  000011010001000                                                                             3        11      -7                                       2152  000100001101000                                                                             3        11      -7                                       2224  000100010110000                                                                             3        11      -7                                       2228  000100010110100                                                                             3        11      -5                                       2281  000100011101001                                                                             3        11      -3                                       2579  000101000010011                                                                             3        11      -5                                       2587  000101000011011                                                                             3        11      -3                                       2656  000101001100000                                                                             3        11      -7                                       2824  000101100001000                                                                             3        11      -7                                       3232  000110010100000                                                                             3        11      -7                                       3748  000111010100100                                                                             3        9       -3                                       3821  000111011101101                                                                             3        9       3                                        4188  001000001011100                                                                             3        11      -5                                       4305  001000011010001                                                                             3        11      -5                                       4419  001000101000011                                                                             3        11      -5                                       4449  001000101100001                                                                             3        11      -5                                       4792  001001010111000                                                                             3        9       -3                                       4874  001001100001010                                                                             3        7       -5                                       4944  001001101010000                                                                             3        11      -5                                       5079  001001111010111                                                                             3        11      3                                        5139  001010000010011                                                                             3        11      -5                                       5145  001010000011001                                                                             3        11      -5                                       5312  001010011000000                                                                             3        9       -7                                       5313  001010011000001                                                                             3        11      -5                                       5424  001010100110000                                                                             3        11      -5                                       5535  001010110011111                                                                             3        9       3                                        5619  001010111110011                                                                             3        11      3                                        5649  001011000010001                                                                             3        11      -5                                       5768  001011010001000                                                                             3        11      -5                                       5904  001011100010000                                                                             3        11      -5                                       6154  001100000001010                                                                             3        7       -7                                       6165  001100000010101                                                                             3        7       -5                                       6187  001100000101011                                                                             3        11      -3                                       6304  001100010100000                                                                             3        11      -7                                       6405  001100100000101                                                                             3        11      -5                                       6464  001100101000000                                                                             3        7       -7                                       6465  001100101000001                                                                             3        11      -5                                       6480  001100101010000                                                                             3        11      -5                                       6495  001100101011111                                                                             3        7       3                                        6645  001100111110101                                                                             3        11      3                                        6922  001101100001010                                                                             3        11      -3                                       7087  001101110101111                                                                             3        11      5                                        7127  001101111010111                                                                             3        11      5                                        7147  001101111101011                                                                             3        11      5                                        7428  001110100000100                                                                             3        11      -5                                       7867  001111010111011                                                                             3        11      5                                        7901  001111011011101                                                                             3        11      5                                        7989  001111100110101                                                                             3        11      3                                        8369  010000010110001                                                                             3        11      -5                                       8377  010000010111001                                                                             3        11      -3                                       8394  010000011001010                                                                             3        11      -5                                       8610  010000110100010                                                                             3        11      -5                                       8730  010001000011010                                                                             3        11      -5                                       8734  010001000011110                                                                             3        11      -3                                       8771  010001001000011                                                                             3        11      -5                                       8898  010001011000010                                                                             3        11      -5                                       9230  010010000001110                                                                             3        9       -5                                       9287  010010001000111                                                                             3        9       -3                                       9738  010011000001010                                                                             3        11      -5                                      10252  010100000001100                                                                             3        7       -7                                      10265  010100000011001                                                                             3        7       -5                                      10278  010100000100110                                                                             3        11      -5                                      10290  010100000110010                                                                             3        11      -5                                      10291  010100000110011                                                                             3        11      -3                                      10340  010100001100100                                                                             3        7       -5                                      10348  010100001101100                                                                             3        11      -3                                      10432  010100011000000                                                                             3        7       -7                                      10544  010100100110000                                                                             3        11      -5                                      10624  010100110000000                                                                             3        7       -7                                      10625  010100110000001                                                                             3        7       -7                                      10626  010100110000010                                                                             3        11      -5                                      10627  010100110000011                                                                             3        11      -3                                      10655  010100110011111                                                                             3        7       3                                       10848  010101001100000                                                                             3        7       -5                                      11040  010101100100000                                                                             3        7       -5                                      11056  010101100110000                                                                             3        11      -3                                      11070  010101100111110                                                                             3        9       3                                       11071  010101100111111                                                                             3        7       5                                       11238  010101111100110                                                                             3        7       3                                       11251  010101111110011                                                                             3        7       5                                       11298  010110000100010                                                                             3        11      -5                                      11456  010110011000000                                                                             3        11      -5                                      11488  010110011100000                                                                             3        11      -3                                      11518  010110011111110                                                                             3        11      5                                       11887  010111001101111                                                                             3        11      5                                       11998  010111011011110                                                                             3        11      5                                       12211  010111110110011                                                                             3        11      5                                       12217  010111110111001                                                                             3        11      5                                       12238  010111111001110                                                                             3        11      5                                       12262  010111111100110                                                                             3        11      5                                       12549  011000100000101                                                                             3        11      -5                                      12609  011000101000001                                                                             3        11      -5                                      12669  011000101111101                                                                             3        11      3                                       12704  011000110100000                                                                             3        11      -5                                      12810  011001000001010                                                                             3        11      -5                                      12929  011001010000001                                                                             3        11      -5                                      12960  011001010100000                                                                             3        7       -5                                      12991  011001010111111                                                                             3        7       5                                       13151  011001101011111                                                                             3        11      5                                       13231  011001110101111                                                                             3        11      5                                       13290  011001111101010                                                                             3        7       3                                       13291  011001111101011                                                                             3        11      5                                       13301  011001111110101                                                                             3        7       5                                       13306  011001111111010                                                                             3        11      5                                       13329  011010000010001                                                                             3        11      -5                                      13431  011010001110111                                                                             3        11      3                                       13727  011010110011111                                                                             3        11      5                                       14254  011011110101110                                                                             3        11      5                                       14354  011100000010010                                                                             3        9       -5                                      14717  011100101111101                                                                             3        11      5                                       14752  011100110100000                                                                             3        7       -3                                      14842  011100111111010                                                                             3        11      5                                       14971  011101001111011                                                                             3        11      5                                       15094  011101011110110                                                                             3        11      5                                       15307  011101111001011                                                                             3        11      5                                       15337  011101111101001                                                                             3        11      5                                       15394  011110000100010                                                                             3        11      -3                                      15547  011110010111011                                                                             3        11      5                                       15802  011110110111010                                                                             3        11      5                                       15978  011111001101010                                                                             3        9       3                                       15979  011111001101011                                                                             3        11      5                                       16051  011111010110011                                                                             3        11      5                                       16057  011111010111001                                                                             3        11      5                                       16181  011111100110101                                                                             3        9       5                                       16217  011111101011001                                                                             3        11      5                                       16282  011111110011010                                                                             3        11      5                                       16485  100000001100101                                                                             3        11      -5                                      16550  100000010100110                                                                             3        11      -5                                      16586  100000011001010                                                                             3        9       -5                                      16710  100000101000110                                                                             3        11      -5                                      16716  100000101001100                                                                             3        11      -5                                      16788  100000110010100                                                                             3        11      -5                                      16789  100000110010101                                                                             3        9       -3                                      16965  100001001000101                                                                             3        11      -5                                      17220  10001101000100                                                                              3        11      -5                                      17373  100001111011101                                                                             3        11      3                                       17430  100010000010110                                                                             3        11      -5                                      17460  100010000110100                                                                             3        11      -5                                      17673  100010100001001                                                                             3        11      -5                                      17796  100010110000100                                                                             3        11      -5                                      17925  100011000000101                                                                             3        11      -5                                      18015  100011001011111                                                                             3        7       3                                       18050  100011010000010                                                                             3        11      -5                                      18413  100011111101101                                                                             3        9       5                                       18513  100100001010001                                                                             3        11      -5                                      19040  100101001100000                                                                             3        11      -5                                      19336  100101110001000                                                                             3        11      -3                                      19438  100101111101110                                                                             3        11      5                                       19461  100110000000101                                                                             3        11      -5                                      19466  100110000001010                                                                             3        7       -5                                      19476  100110000010100                                                                             3        11      -5                                      19477  100110000010101                                                                             3        7       -3                                      19536  100110001010000                                                                             3        11      -5                                      19616  100110010100000                                                                             3        11      -5                                      19776  100110101000000                                                                             3        7       -5                                      19807  100110101011111                                                                             3        7       5                                       19838  100110010111110                                                                             3        11      5                                       19957  100110111110101                                                                             3        11      5                                       20063  100111001011111                                                                             3        11      5                                       20098  100111010000010                                                                             3        11      -3                                      20158  100111010111110                                                                             3        11      5                                       20218  100111011111010                                                                             3        11      5                                       20505  10100000000101                                                                              3        11      -5                                      20529  101000000110001                                                                             3        11      -5                                      20550  101000001000110                                                                             3        11      -5                                      20556  101000001001100                                                                             3        11      -5                                      20769  101000100100001                                                                             3        11      -5                                      20880  101000110010000                                                                             3        11      -5                                      21249  101001100000001                                                                             3        11      -5                                      21279  101001100011111                                                                             3        11      3                                       21311  101001100111111                                                                             3        11      5                                       21469  101001111011101                                                                             3        11      5                                       21516  101010000001100                                                                             3        7       -5                                      21529  101010000011001                                                                             3        7       -3                                      21696  101010011000000                                                                             3        7       -5                                      21697  101010011000001                                                                             3        9       -3                                      21711  101010011001111                                                                             3        11      3                                       21727  101010011011111                                                                             3        7       5                                       21919  101010110011111                                                                             3        7       5                                       22112  101011001100000                                                                             3        7       -3                                      22140  101011001111100                                                                             3        11      3                                       22141  101011001111101                                                                             3        11      5                                       22142  101011001111110                                                                             3        9       5                                       22143  101011001111111                                                                             3        7       7                                       22223  101011011001111                                                                             3        11      5                                       22335  101011100111111                                                                             3        7       7                                       22419  101011110010011                                                                             3        11      3                                       22427  101011110011011                                                                             3        7       5                                       22476  101011111001100                                                                             3        11      3                                       22477  101011111001101                                                                             3        11      5                                       22489  101011111011001                                                                             3        11      5                                       22502  10101111110110                                                                              3        7       5                                       22515  101011111110011                                                                             3        7       7                                       23029  101100111110101                                                                             3        11      5                                       23480  101101110111000                                                                             3        9       3                                       23537  101101111110001                                                                             3        9       5                                       23869  101110100111101                                                                             3        11      5                                       23996  101110110111100                                                                             3        11      5                                       24033  101110111100001                                                                             3        11      3                                       24037  101110111100101                                                                             3        11      5                                       24157  101111001011101                                                                             3        11      5                                       24373  101111100110101                                                                             3        11      5                                       24390  101111101000110                                                                             3        11      3                                       24398  101111101001110                                                                             3        11      5                                       24778  110000011001010                                                                             3        11      -3                                      24866  110000100100010                                                                             3        11      -5                                      24900  110000101000100                                                                             3        11      -5                                      25339  110001011111011                                                                             3        11      5                                       25620  110010000010100                                                                             3        11      -5                                      25640  110010000101000                                                                             3        11      -5                                      25680  110010001010000                                                                             3        11      -5                                      25845  110010011110101                                                                             3        11      3                                       26122  110011000001010                                                                             3        11      -3                                      26272  110011010100000                                                                             3        7       -3                                      26287  110011010101111                                                                             3        11      5                                       26302  110011010111110                                                                             3        11      5                                       26303  110011010111111                                                                             3        7       7                                       26362  110011011111010                                                                             3        11      5                                       26463  110011101011111                                                                             3        11      7                                       26580  110011111010100                                                                             3        11      3                                       26602  110011111101010                                                                             3        7       5                                       26613  110011111110101                                                                             3        7       7                                       26863  110100011101111                                                                             3        11      5                                       26999  110100101110111                                                                             3        11      5                                       27118  110100111101110                                                                             3        11      5                                       27148  110101000001100                                                                             3        11      -3                                      27232  110101001100000                                                                             3        9       -3                                      27343  110101011001111                                                                             3        11      5                                       27454  110101100111110                                                                             3        11      5                                       27455  110101100111111                                                                             3        9       7                                       27622  110101111100110                                                                             3        11      5                                       27628  110101111101100                                                                             3        11      5                                       27688  110110000101000                                                                             3        11      -3                                      27823  110110010101111                                                                             3        11      5                                       27893  110110011110101                                                                             3        7       5                                       27975  110110101000111                                                                             3        9       3                                       28318  110111010011110                                                                             3        11      5                                       28348  110111010111100                                                                             3        11      5                                       28462  110111100101110                                                                             3        11      5                                       28579  110111110100011                                                                             3        11      5                                       28946  111000100010010                                                                             3        9       -3                                      29019  111000101011011                                                                             3        9       3                                       29535  111001101011111                                                                             3        11      7                                       29943  111010011110111                                                                             3        11      7                                       30111  111010110011111                                                                             3        11      7                                       30180  111010111100100                                                                             3        11      3                                       30188  111010111101100                                                                             3        11      5                                       30486  111011100010110                                                                             3        11      3                                       30539  111011101001011                                                                             3        11      5                                       30543  111011101001111                                                                             3        11      7                                       30615  111011110010111                                                                             3        11      7                                       31095  111100101110111                                                                             3        11      7                                       31125  111100110010101                                                                             3        11      3                                       31147  111100110101011                                                                             3        11      5                                       31157  111100110110101                                                                             3        11      5                                       31387  111101010011011                                                                             3        11      5                                       31411  111101010110011                                                                             3        11      5                                       31462  111101011100110                                                                             3        11      5                                       31468  111101011101100                                                                             3        11      5                                       31546  111101100111010                                                                             3        11      5                                       31627  111101110001011                                                                             3        11      5                                       31845  111110001100101                                                                             3        11      3                                       31946  111110011001010                                                                             3        7       3                                       31956  111110011010100                                                                             3        9       3                                       31957  111110011010101                                                                             3        7       5                                       31958  111110011010110                                                                             3        11      5                                       31959  111110011010111                                                                             3        11      7                                       32049  111110100110001                                                                             3        7       3                                       32057  111110100111001                                                                             3        11      5                                       32076  111110101001100                                                                             3        7       3                                       32089  111110101011001                                                                             3        7       5                                       32102  111110101100110                                                                             3        11      5                                       32103  111110101100111                                                                             3        11      7                                       32115  111110101110011                                                                             3        11      7                                       32149  111110110010101                                                                             3        7       5                                       32357  111111001100101                                                                             3        11      5                                       32362  111111001101010                                                                             3        7       5                                       32363  111111001101011                                                                             3        9       7                                       32373  111111001110101                                                                             3        7       7                                       32422  111111010100110                                                                             3        7       5                                       32435  111111010110011                                                                             3        7       7                                       32565  111111100110101                                                                             3        7       7                                       ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        (n = 17)                                                                                           max. corr.                                                                              max. corr.                                     number bj            (forward) (back) dc level                                ______________________________________                                        2931   00000101101110011                                                                           3         9      -1                                      3253   00000110010110101                                                                           3         9      -3                                      3286   00000110011010110                                                                           3         9      -3                                      3685   00000111001100101                                                                           3         13     -3                                      3693   00000111001101101                                                                           3         11     -1                                      3893   00000111100110101                                                                           3         9      -1                                      3929   00000111101011001                                                                           3         11     -1                                      5555   00001010110110011                                                                           3         9      -1                                      5838   00001011011001110                                                                           3         11     -1                                      6443   00001100100101011                                                                           3         9      -3                                      6581   00001100110110101                                                                           3         13     -1                                      6775   00001101001110111                                                                           3         13     1                                       6877   00001101011011101                                                                           3         9      1                                       7386   00001110011011010                                                                           3         11     -1                                      7642   00001110111011010                                                                           3         9      1                                       7859   00001111010110011                                                                           3         9      1                                       7901   00001111011011101                                                                           3         11     3                                       7917   00001111011101101                                                                           3         13     3                                       9039   00010001101001111                                                                           3         13     -1                                      9125   00010001110100101                                                                           3         11     -3                                      9171   00010001111010011                                                                           3         9      -1                                      9189   00010001111100101                                                                           3         9      -1                                      11111  00010101101100111                                                                           3         9      1                                       12121  00010111101011001                                                                           3         9      1                                       12887  00011001001010111                                                                           3         9      -1                                      14773  00011100110110101                                                                           3         11     1                                       15269  00011101110100101                                                                           3         13     1                                       15284  00011101110110100                                                                           3         9      1                                       15716  00011110101100100                                                                           3         11     -1                                      15718  00011110101100110                                                                           3         9      1                                       16217  00011111101011001                                                                           3         9      3                                       17596  00100010010111100                                                                           3         13     -3                                      18110  00100011010111110                                                                           3         9      1                                       19499  00100110000101011                                                                           3         13     -3                                      19578  00100110001111010                                                                           3         11     -1                                      19832  00100110101111000                                                                           3         11     -1                                      20590  00101000001101110                                                                           3         9      -3                                      20716  00101000011101100                                                                           3         13     -3                                      21054  00101001000111110                                                                           3         13     -1                                      21310  00101001100111110                                                                           3         9      1                                       22223  00101011011001111                                                                           3         9      3                                       22427  00101011110011011                                                                           3         13     3                                       23075  00101101000100011                                                                           3         13     -3                                      23480  00101101110111000                                                                           3         9      1                                       24749  00110000010101101                                                                           3         9      -3                                      24757  00110000010110101                                                                           3         11     -3                                      24765  00110000010111101                                                                           3         9      -1                                      25183  00110001001011111                                                                           3         9      1                                       25775  00110010010101111                                                                           3         9      1                                       25871  00110010100001111                                                                           3         9      -1                                      26578  00110011111010010                                                                           3         9      1                                       26743  00110100001110111                                                                           3         9      1                                       28180  00110111000010100                                                                           3         13     -3                                      30539  00111011101001011                                                                           3         13     3                                       31300  00111101001000100                                                                           3         13     -3                                      31946  00111110011001010                                                                           3         9      1                                       31958  00111110011010110                                                                           3         13     3                                       33229  01000000111001101                                                                           3         9      -3                                      34291  01000010111110011                                                                           3         9      1                                       35087  01000100100001111                                                                           3         11     -3                                      35151  01000100101001111                                                                           3         9      -1                                      35193  01000100101111001                                                                           3         9      -1                                      35301  01000100111100101                                                                           3         13     -1                                      37135  01001000100001111                                                                           3         13     -3                                      37150  01001000100011110                                                                           3         9      -3                                      37663  01001001100011111                                                                           3         11     1                                       38387  01001010111110011                                                                           3         9      3                                       38860  01001011111001100                                                                           3         9      1                                       38862  01001011111001110                                                                           3         11     3                                       39165  01001100011111101                                                                           3         9      3                                       41433  01010000111011001                                                                           3         9      -1                                      42183  01010010011000111                                                                           3         11     -1                                      42191  01010010011001111                                                                           3         13     1                                       42399  01010010110011111                                                                           3         9      3                                       42483  01010010111110011                                                                           3         11     3                                       42527  01010011000011111                                                                           3         9      1                                       42620  01010011001111100                                                                           3         9      1                                       45175  01011000001110111                                                                           3         9      1                                       45277  01011000011011101                                                                           3         13     1                                       45855  01011001100011111                                                                           3         13     3                                       45953  01011001110000001                                                                           3         9      -3                                      46105  01011010000011001                                                                           3         9      -3                                      46151  010110100001000111                                                                          3         13     -1                                      46199  01011010001110111                                                                           3         11     3                                       46704  01011011001110000                                                                           3         11     -1                                      46960  01011011101110000                                                                           3         9      1                                       48228  01011110001100100                                                                           3         11     -1                                      48921  01011111100011001                                                                           3         9      3                                       49885  01100001011011101                                                                           3         9      1                                       50366  01100010010111110                                                                           3         13     1                                       51445  01100100011110101                                                                           3         9      1                                       51719  01100101000000111                                                                           3         9      -3                                      51735  01100101000010111                                                                           3         9      -1                                      51743  01100101000011111                                                                           3         11     1                                       52600  01100110101111000                                                                           3         9      1                                       52741  01100111000000101                                                                           3         9      -3                                      53157  01100111110100101                                                                           3         9      3                                       53486  01101000011101110                                                                           3         13     1                                       54880  01101011001100000                                                                           3         9      -3                                      54908  01101011001111100                                                                           3         13     3                                       56801  01101110111100001                                                                           3         13     3                                       59009  01110011010000001                                                                           3         13     -3                                      59088  01110011011010000                                                                           3         11     -1                                      59346  01110011111010010                                                                           3         11     3                                       60436  01110110000010100                                                                           3         9      -3                                      60950  01110111000010110                                                                           3         13     1                                       61577  01111000010001001                                                                           3         13     -3                                      61714  01111000100010010                                                                           3         9      -3                                      63636  01111100010010100                                                                           3         13     -1                                      63892  01111100110010100                                                                           3         9      1                                       64070  01111101001000110                                                                           3         13     1                                       64196  01111110001100101                                                                           3         9      1                                       64613  01111110001100101                                                                           3         9      3                                       64817  01111110100110001                                                                           3         13     3                                       66254  10000001011001110                                                                           3         13     -3                                      66458  10000001110011010                                                                           3         9      -3                                      66875  10000010100111011                                                                           3         9      -1                                      67001  10000010110111001                                                                           3         13     -1                                      67179  10000011001101011                                                                           3         9      -1                                      67435  10000011101101011                                                                           3         13     1                                       69357  10000111011101101                                                                           3         9      3                                       69494  10000111101110110                                                                           3         13     3                                       70121  10001000111101001                                                                           3         13     -1                                      70635  10001001111101011                                                                           3         9      3                                       71725  10001100000101101                                                                           3         11     -3                                      71983  10001100100101111                                                                           3         11     1                                       72062  10001100101111110                                                                           3         13     3                                       74270  10010001000011110                                                                           3         13     -3                                      76163  10010100110000011                                                                           3         13     -3                                      76191  10010100110011111                                                                           3         9      3                                       77585  10010111100010001                                                                           3         13     -1                                      77914  10011000001011010                                                                           3         9      -3                                      78330  10011000111111010                                                                           3         9      3                                       78471  10011001010000111                                                                           3         9      -1                                      79328  10011010111100000                                                                           3         11     -1                                      79336  10011010111101000                                                                           3         9      1                                       79352  10011010111111000                                                                           3         9      3                                       79626  10011011100001010                                                                           3         9      -1                                      80705  10011101101000001                                                                           3         13     -1                                      81186  10011110100100010                                                                           3         9      -1                                      82150  10100000011100110                                                                           3         9      -3                                      82843  10100001110011011                                                                           3         11     1                                       84111  10100100010001111                                                                           3         9      -1                                      84367  10100100110001111                                                                           3         11     1                                       84872  10100101110001000                                                                           3         11     -3                                      84920  10100101110111000                                                                           3         13     1                                       84966  10100101111100110                                                                           3         9      3                                       85118  10100110001111110                                                                           3         9      3                                       85216  10100110011100000                                                                           3         13     -3                                      85794  10100111100100010                                                                           3         13     -1                                      85896  10100111110001000                                                                           3         9      -1                                      88451  10101100110000011                                                                           3         9      -1                                      88544  10101100111100000                                                                           3         9      -1                                      88588  10101101000001100                                                                           3         11     -3                                      88672  10101101001100000                                                                           3         9      -3                                      88880  10101101100110000                                                                           3         13     -1                                      88888  10101101100111000                                                                           3         11     1                                       89638  10101111000100110                                                                           3         9      1                                       91906  10110011100000010                                                                           3         9      -3                                      92209  10110100000110001                                                                           3         11     -3                                      92211  10110100000110011                                                                           3         9      -1                                      92684  10110101000001100                                                                           3         9      -3                                      93408  10110110011100000                                                                           3         11     -1                                      93921  10110111011100001                                                                           3         9      3                                       93936  10110111011110000                                                                           3         13     3                                       95770  10111011000011010                                                                           3         13     1                                       95878  10111011010000110                                                                           3         9      1                                       95920  10111011010110000                                                                           3         9      1                                       95984  10111011011110000                                                                           3         11     3                                       96780  10111101000001100                                                                           3         9      -1                                      97842  10111111000110010                                                                           3         9      3                                       99113  11000001100101001                                                                           3         13     -3                                      99125  11000001100110101                                                                           3         9      -1                                      99771  11000010110111011                                                                           3         13     3                                       100532 11000100010110100                                                                           3         13     -3                                      102891 11001000111101011                                                                           3         13     3                                       104328 11001011110001000                                                                           3         9      -1                                      104493 11001100000101101                                                                           3         9      -1                                      105200 11001101011110000                                                                           3         9      1                                       105296 11001101101010000                                                                           3         9      -1                                      105888 11001110110100000                                                                           3         9      -1                                      106306 11001111101000010                                                                           3         9      1                                       106314 11001111101001010                                                                           3         11     3                                       106322 11001111101010010                                                                           3         9      3                                       107591 11010010001000111                                                                           3         9      -1                                      107996 11010010111011100                                                                           3         13     3                                       108644 11010100001100100                                                                           3         13     -3                                      108848 11010100100110000                                                                           3         9      -3                                      109761 11010110011000001                                                                           3         9      -1                                      110017 11010110111000001                                                                           3         13     1                                       110355 11010111100010011                                                                           3         13     3                                       110481 11010111110010001                                                                           3         9      3                                       111239 11011001010000111                                                                           3         11     1                                       111493 11011001110000101                                                                           3         11     1                                       111572 11011001111010100                                                                           3         13     3                                       112961 11011100101000001                                                                           3         9      -1                                      113475 11011101101000011                                                                           3         13     3                                       114854 11100000010100110                                                                           3         9      -3                                      115353 11100001010011001                                                                           3         9      -1                                      115355 11100001010011011                                                                           3         11     1                                       115787 11100010001001011                                                                           3         9      -1                                      115802 11100010001011010                                                                           3         13     -1                                      116298 11100011001001010                                                                           3         11     -1                                      118184 11100110110101000                                                                           3         9      1                                       118950 11101000010100110                                                                           3         9      -1                                      119960 11101010010011000                                                                           3         9      -1                                      121882 11101110000011010                                                                           3         9      1                                       121900 11101110000101100                                                                           3         9      1                                       121946 11101110001011010                                                                           3         11     3                                       122032 11101110010110000                                                                           3         13     1                                       123154 11110000100010010                                                                           3         13     -3                                      123170 11110000100100010                                                                           3         11     -3                                      123212 11110000101001100                                                                           3         9      -1                                      123429 11110001000100101                                                                           3         9      -1                                      123685 11110001100100101                                                                           3         11     1                                       124194 11110010100100010                                                                           3         9      -1                                      124296 11110010110001000                                                                           3         13     -1                                      124490 11110011001001010                                                                           3         13     1                                       124628 11110011011010100                                                                           3         9      3                                       125233 11110100100110001                                                                           3         11     1                                       125516 11110101001001100                                                                           3         9      1                                       127142 11111000010100110                                                                           3         11     1                                       127178 11111000011001010                                                                           3         9      1                                       127378 11111000110010010                                                                           3         11     1                                       127386 11111000110011010                                                                           3         13     3                                       127785 11111001100101001                                                                           3         9      3                                       127818 11111001101001010                                                                           3         9      3                                       128140 11111010010001100                                                                           3         9      1                                       ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        (n = 19)                                                                                            max. corr.                                                                              max. corr.                                    number bj             (forward) (back) dc level                               ______________________________________                                        3241   0000000110010101001                                                                          3         15     -7                                     10342  0000010100001100110                                                                          3         15     -7                                     26897  0000110100100010001                                                                          3         15     -7                                     28946  0000111000100010010                                                                          3         7      -7                                     33705  0001000001110101001                                                                          3         11     -5                                     34996  0001000100010110100                                                                          3         11     -7                                     37560  0001001001010111000                                                                          3         15     -5                                     59976  0001110101001001000                                                                          3         15     -5                                     61146  0001110111011011010                                                                          3         7      3                                      64429  0001111101110101101                                                                          3         9      5                                      66385  0010000001101010001                                                                          3         11     -7                                     70117  0010001000111100101                                                                          3         15     -3                                     74076  0010010000101011100                                                                          3         15     -5                                     86785  0010101001100000001                                                                          3         15     -7                                     92296  0010110100010001000                                                                          3         11     -7                                     95265  0010111010000100001                                                                          3         11     -5                                     97651  0010111110101110011                                                                          3         15     5                                      100875 0011000101000001011                                                                          3         15     -5                                     104970 0011001101000001010                                                                          3         15     -5                                     119844 0011101010000100100                                                                          3         15     -5                                     129885 0011111101101011101                                                                          3         11     7                                      130261 0011111110011010101                                                                          3         15     5                                      139806 0100010001000011110                                                                          3         11     -5                                     141571 0100010100100000011                                                                          3         11     -7                                     145426 0100011100000010010                                                                          3         15     -7                                     147682 0100100000011100010                                                                          3         15     -7                                     148592 0100100010001110000                                                                          3         7      -7                                     151815 0100101000100000111                                                                          3         9      -5                                     164556 0101000001011001100                                                                          3         15     -5                                     173571 0101010011000000011                                                                          3         15     -5                                     181179 0101100001110111011                                                                          3         15     3                                      187320 0101101101110111000                                                                          3         7      3                                      204961 0110010000010100001                                                                          3         15     -7                                     209056 0110011000010100000                                                                          3         15     -7                                     217591 0110101000111110111                                                                          3         11     5                                      218751 0110101011001111111                                                                          3         15     7                                      229006 0110111111010001110                                                                          3         15     5                                      232438 0111000101111110110                                                                          3         15     5                                      240123 0111010100111111011                                                                          3         11     7                                      244559 0111011101101001111                                                                          3         15     7                                      246306 0111100001000100010                                                                          3         11     -5                                     251865 0111101011111011001                                                                          3         15     7                                      253579 0111101111010001011                                                                          3         11     5                                      260523 0111111100110101011                                                                          3         15     7                                      263764 1000000011001010100                                                                          3         15     -7                                     270708 1000010000101110100                                                                          3         11     -5                                     272422 1000010100000100110                                                                          3         15     -7                                     277981 1000011110111011101                                                                          3         11     5                                      279728 1000100010010110000                                                                          3         15     -7                                     284164 1000101011000000100                                                                          3         11     -7                                     291849 1000111010000001001                                                                          3         15     -5                                     295281 1001000000101110001                                                                          3         15     -5                                     305536 1001010100110000000                                                                          3         15     -7                                     306696 1001010111000001000                                                                          3         11     -5                                     315231 1001100111101011111                                                                          3         15     7                                      319326 1001101111101011110                                                                          3         15     7                                      336967 1010010010001000111                                                                          3         7      -3                                     343108 1010011110001000100                                                                          3         15     -3                                     350716 1010101100111111100                                                                          3         15     5                                      359731 1010111110100110011                                                                          3         15     5                                      372472 1011010111011111000                                                                          3         9      5                                      375695 1011011101110001111                                                                          3         7      7                                      376605 1011011111100011101                                                                          3         15     7                                      378861 1011100011111101101                                                                          3         15     7                                      382716 1011101011011111100                                                                          3         11     7                                      384481 1011101110111100001                                                                          3         11     5                                      394026 1100000001100101010                                                                          3         15     -5                                     394402 1100000010010100010                                                                          3         11     -7                                     404443 1100010101111011011                                                                          3         15     5                                      419317 1100110010111110101                                                                          3         15     5                                      423412 1100111010111110100                                                                          3         15     5                                      426636 1101000001010001100                                                                          3         15     -5                                     429022 1101000101111011110                                                                          3         11     5                                      431991 1101001011101110111                                                                          3         11     7                                      437502 1101010110011111110                                                                          3         15     7                                      450211 1101101111010100011                                                                          3         15     5                                      454170 1101110111000011010                                                                          3         15     3                                      457902 1101111110010101110                                                                          3         11     7                                      459858 1110000010001010010                                                                          3         9      -5                                     463141 1110001000100100101                                                                          3         7      -3                                     464311 1110001010110110111                                                                          3         15     5                                      486727 1110110110101000111                                                                          3         15     5                                      489291 1110111011101001011                                                                          3         11     7                                      490582 1110111110001010110                                                                          3         11     5                                      495341 1111000111011101101                                                                          3         7      7                                      497390 1111001011011101110                                                                          3         15     7                                      513945 1111101011110011001                                                                          3         15     7                                      521046 1111111001101010110                                                                          3         15     7                                      ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                        (n = 21)                                                                                             max. corr.                                                                             max. corr.                                                                            dc                                    number bj              (forward)                                                                              (backward)                                                                            level                                 ______________________________________                                        14773  000000011100110110101                                                                         3        15      -3                                    23865  000000101110100111001                                                                         3        13      -3                                    29546  000000111001101101010                                                                         3        11      -3                                    31157  000000111100110110101                                                                         3        11      -1                                    47731  000001011101001110011                                                                         3        15      -1                                    55754  000001101100111001010                                                                         3        11      -3                                    59029  000001110011010010101                                                                         3        11      -3                                    59093  000001110011011010101                                                                         3        15      -1                                    59245  000001110011101101101                                                                         3        15      1                                     60249  000001110101101011001                                                                         3        15      -1                                    62294  000001111001101010110                                                                         3        17      -1                                    81210  000010011110100111010                                                                         3        15      -1                                    89708  000010101111001101100                                                                         3        21      -1                                    183260 000101100101111011100                                                                         3        17      1                                     231861 000111000100110110101                                                                         3        15      -1                                    248388 000111100101001000100                                                                         3        13      -5                                    255570 000111110011001010010                                                                         3        13      -1                                    257750 000111110111011010110                                                                         3        13      5                                     276270 001000011011100101110                                                                         3        11      -1                                    281208 001000100101001111000                                                                         3        13      -5                                    281571 001000100101111100011                                                                         3        13      -1                                    331699 001010000111110110011                                                                         3        15      1                                     336446 001010010001000111110                                                                         3        13      -3                                    397237 001100000111110110101                                                                         3        15      1                                     406623 001100011010001011111                                                                         3        15      1                                     410091 001100100000111101011                                                                         3        15      -1                                    442901 001101100001000010101                                                                         3        13      -5                                    446288 001101100111101010000                                                                         3        21      -1                                    459446 001110000001010110110                                                                         3        11      -3                                    460219 001110000010110111011                                                                         3        13      1                                     490088 001110111101001101000                                                                         3        17      1                                     509010 001111100010001010010                                                                         3        13      -3                                    521034 001111111001101001010                                                                         3        17      3                                     521046 001111111001101010110                                                                         3        17      5                                     549238 010000110000101110110                                                                         3        17      -3                                    598815 010010010001100011111                                                                         3        15      -1                                    607356 010010100010001111100                                                                         3        13      -3                                    609528 010010100110011111000                                                                         3        13      -1                                    614638 010010110000011101110                                                                         3        13      -1                                    659673 010100001000011011001                                                                         3        15      -5                                    672243 010100100000111110011                                                                         3        15      -1                                    674879 010100100110000111111                                                                         3        11      1                                     674943 010100100110001111111                                                                         3        15      3                                     675271 010100100110111000111                                                                         3        15      1                                     678396 010100101100111111100                                                                         3        17      3                                     684896 010100111001101100000                                                                         3        11      -3                                    693023 010101001001100011111                                                                         3        15      1                                     709407 010101101001100011111                                                                         3        11      3                                     711104 010101101100111000000                                                                         3        11      -3                                    718739 010101111011110010011                                                                         3        13      5                                     759696 010111001011110010000                                                                         3        15      -1                                    783558 010111111010011000110                                                                         3        21      3                                     812538 011000110010111111010                                                                         3        21      3                                     813247 011000110100010111111                                                                         3        13      3                                     827125 011001001111011110101                                                                         3        15      5                                     828703 011001010010100011111                                                                         3        15      1                                     846657 011001110101101000001                                                                         3        15      -1                                    874976 011010101100111100000                                                                         3        17      -1                                    875004 011010101100111111100                                                                         3        17      5                                     880376 011010110111011111000                                                                         3        13      5                                     895004 011011010100000011100                                                                         3        11      -3                                    896785 011011010111100010001                                                                         3        13      1                                     905410 011011101000011000010                                                                         3        17      -3                                    957828 011101001110110000100                                                                         3        11      -1                                    975058 011101110000011010010                                                                         3        13      -1                                    975177 011101110000101001001                                                                         3        13      -1                                    1018004                                                                              011111000100010010100                                                                         3        13      -3                                    1025305                                                                              011111010010100011001                                                                         3        15      1                                     1071846                                                                              100000101101011100110                                                                         3        15      -1                                    1079147                                                                              100000111011101101011                                                                         3        13      3                                     1121974                                                                              100010001111010110110                                                                         3        13      1                                     1122093                                                                              100010001111100101101                                                                         3        13      1                                     1139323                                                                              100010110001001111011                                                                         3        11      1                                     1191741                                                                              100100010111100111101                                                                         3        17      3                                     1200366                                                                              100100101000011101110                                                                         3        13      -1                                    1202147                                                                              100100101011111100011                                                                         3        11      3                                     1216775                                                                              100101001000100000111                                                                         3        13      -5                                    1222147                                                                              100101010011000000011                                                                         3        17      -5                                    1222175                                                                              100101010011000011111                                                                         3        17      1                                     1250494                                                                              100110001010010111110                                                                         3        15      1                                     1268448                                                                              100110101101011100000                                                                         3        15      -1                                    1270026                                                                              100110110000100001010                                                                         3        15      -5                                    1283904                                                                              100111001011101000000                                                                         3        13      -3                                    1284613                                                                              100111001101000000101                                                                         3        21      -3                                    1313593                                                                              101000000101100111001                                                                         3        21      -3                                    1337455                                                                              101000110100001101111                                                                         3        15      1                                     1378412                                                                              101010000100001101100                                                                         3        13      -5                                    1386047                                                                              101010010011000111111                                                                         3        11      3                                     1387744                                                                              101010010110011100000                                                                         3        11      -3                                    1404128                                                                              101010110110011100000                                                                         3        15      -1                                    1412255                                                                              101011000110010011111                                                                         3        11      3                                     1418755                                                                              101011010011000000011                                                                         3        17      -3                                    1421880                                                                              101011011001000111000                                                                         3        15      -1                                    1422208                                                                              101011011001110000000                                                                         3        15      -3                                    1422272                                                                              101011011001111000000                                                                         3        11      -1                                    1424908                                                                              101011011111000001100                                                                         3        15      1                                     1437478                                                                              101011110111100100110                                                                         3        15      5                                     1482513                                                                              101101001111100010001                                                                         3        13      1                                     1487623                                                                              101101011001100000111                                                                         3        13      1                                     1489795                                                                              101101011101110000011                                                                         3        13      3                                     1498336                                                                              101101101110011100000                                                                         3        15      1                                     1547913                                                                              101111001111010001001                                                                         3        17      3                                     1576105                                                                              110000000110010101001                                                                         3        17      -5                                    1576117                                                                              110000000110010110101                                                                         3        17      3                                     1588141                                                                              110000011101110101101                                                                         3        13      3                                     1607063                                                                              110001000010110010111                                                                         3        17      -1                                    1636932                                                                              110001111101001000100                                                                         3        13      -1                                    1637705                                                                              110001111110101001001                                                                         3        11      3                                     1650863                                                                              110010011000010101111                                                                         3        21      1                                     1654250                                                                              110010011110111101010                                                                         3        13      5                                     1687060                                                                              110011011111000010100                                                                         3        15      1                                     1690528                                                                              110011100101110100000                                                                         3        15      -1                                    1699914                                                                              110011111000001001010                                                                         3        15      -1                                    1760705                                                                              110101101110111000001                                                                         3        13      3                                     1765452                                                                              110101111000001001100                                                                         3        15      -1                                    1815580                                                                              110111011010000011100                                                                         3        13      1                                     1815943                                                                              110111011010110000111                                                                         3        13      5                                     1820881                                                                              110111100100011010001                                                                         3        11      1                                     1839401                                                                              111000001000100101001                                                                         3        13      -5                                    1841581                                                                              111000001100110101101                                                                         3        13      1                                     1848763                                                                              111000011010110111011                                                                         3        13      5                                     1865290                                                                              111000111011001001010                                                                         3        15      1                                     1913891                                                                              111010011010000100011                                                                         3        17      -1                                    2007443                                                                              111101010000110010011                                                                         3        21      1                                     2015941                                                                              111101100001011000101                                                                         3        15      1                                     2034857                                                                              111110000110010101001                                                                         3        17      1                                     2036902                                                                              111110001010010100110                                                                         3        15      1                                     2037906                                                                              111110001100010010010                                                                         3        15      -1                                    2038058                                                                              111110001100100101010                                                                         3        15      1                                     2038122                                                                              111110001100101101010                                                                         3        11      3                                     2041397                                                                              111110010011000110101                                                                         3        11      3                                     2049420                                                                              111110100010110001100                                                                         3        15      1                                     2065994                                                                              111111000011001001010                                                                         3        11      1                                     2067605                                                                              111111000110010010101                                                                         3        11      3                                     2073286                                                                              111111010001011000110                                                                         3        13      3                                     2082378                                                                              111111100011001001010                                                                         3        15      3                                     ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        (n = 23)                                                                                              max.                                                                          corr.                                                                         (for-  max. corr.                                     number bj               ward)  (backward)                                                                            dc level                               ______________________________________                                        29362  00000000111001010110010                                                                        3      15      -7                                     75541  00000010010011100010101                                                                        3      11      -7                                     86422  00000010101000110010110                                                                        3      15      -7                                     115861 00000011100010010010101                                                                        3      11      -7                                     271825 00001000010010111010001                                                                        3      11      -7                                     272197 00001000010011101000101                                                                        3      15      -7                                     333508 00001010001011011000100                                                                        3      11      -7                                     345892 00001010100011100100100                                                                        3      15      -7                                     463141 00001110001000100100101                                                                        3      11      -7                                     476197 00001110100010000100101                                                                        3      11      -7                                     496708 00001111001010001000100                                                                        3      15      -7                                     543651 00010000100101110100011                                                                        3      11      -5                                     789930 00011000000110110101010                                                                        3      15      -5                                     1031085                                                                              00011111011101110101101                                                                        3      11      7                                      1082833                                                                              00100001000010111010001                                                                        3      11      -7                                     1083205                                                                              00100001000011101000101                                                                        3      11      -7                                     1116052                                                                              00100010000011110010100                                                                        3      11      -7                                     1119472                                                                              00100010001010011110000                                                                        3      15      -7                                     1142932                                                                              00100010111000010010100                                                                        3      11      -7                                     1160272                                                                              00100011011010001010000                                                                        3      11      -7                                     1181041                                                                              00100100000010101110001                                                                        3      15      -7                                     1208656                                                                              00100100111000101010000                                                                        3      15      -7                                     1345348                                                                              00101001000011101000100                                                                        3      11      -7                                     1372228                                                                              00101001111000001000100                                                                        3      11      -7                                     1524769                                                                              00101110100010000100001                                                                        3      11      -7                                     1906423                                                                              00111010001011011110111                                                                        3      11      5                                      1994730                                                                              00111100110111111101010                                                                        3      15      7                                      2285833                                                                              01000101110000100001001                                                                        3      11      -7                                     2429191                                                                              01001010001000100000111                                                                        3      11      -7                                     2533120                                                                              01001101010011100000000                                                                        3      15      -7                                     2807832                                                                              01010101101100000011000                                                                        3      15      -5                                     2846271                                                                              01010110110111000111111                                                                        3      11      7                                      2854335                                                                              01010111000110110111111                                                                        3      11      7                                      2882364                                                                              01010111111101100111100                                                                        3      15      7                                      2965230                                                                              01011010011111011101110                                                                        3      15      7                                      2997135                                                                              01011011011101110001111                                                                        3      11      7                                      3010191                                                                              01011011110111010001111                                                                        3      11      7                                      3050991                                                                              01011101000110111101111                                                                        3      15      7                                      3051387                                                                              01011101000111101111011                                                                        3      11      7                                      3128430                                                                              01011111011110001101110                                                                        3      11      7                                      3141006                                                                              01011111110110110001110                                                                        3      15      7                                      3458368                                                                              01101001100010101000000                                                                        3      15      -7                                     3652701                                                                              01101111011110001011101                                                                        3      11      7                                      3715035                                                                              01110001010111111011011                                                                        3      15      7                                      3726330                                                                              01110001101101111111010                                                                        3      15      7                                      3812847                                                                              0111010001011011110111                                                                         3      11      7                                      3813243                                                                              01110100010111101111011                                                                        3      11      7                                      3874554                                                                              01110110001111011111010                                                                        3      11      7                                      3910974                                                                              01110111010110100111110                                                                        3      11      7                                      3915354                                                                              01110111011111001011010                                                                        3      15      7                                      3922494                                                                              01110111101101000111110                                                                        3      11      7                                      4058763                                                                              01111011110111010001011                                                                        3      11      7                                      4074990                                                                              01111100010110111101110                                                                        3      11      7                                      4086510                                                                              01111100101101011101110                                                                        3      11      7                                      4302097                                                                              10000011010010100010001                                                                        3      11      -7                                     4313617                                                                              10000011101001000010001                                                                        3      11      -7                                     4329844                                                                              10000100001000101110100                                                                        3      11      -7                                     4466113                                                                              10001000010010111000001                                                                        3      11      -7                                     4473253                                                                              10001000100000110100101                                                                        3      15      -7                                     4477633                                                                              10001000101001011000001                                                                        3      11      -7                                     4514053                                                                              10001001110000100000101                                                                        3      11      -7                                     4575364                                                                              1000101110100001000010                                                                         3      11      -7                                     4575760                                                                              10001011101001000010000                                                                        3      11      -7                                     4662277                                                                              10001110010010000000101                                                                        3      15      -7                                     4673572                                                                              10001110101000000100100                                                                        3      15      -7                                     4735906                                                                              10010000100001110100010                                                                        3      11      -7                                     4930239                                                                              10010110011101010111111                                                                        3      15      7                                      5247601                                                                              10100000001001001110001                                                                        3      15      7                                      5260177                                                                              10100000100001110010001                                                                        3      11      -7                                     5337220                                                                              10100010111000010000100                                                                        3      11      -7                                     5337616                                                                              10100010111001000010000                                                                        3      15      -7                                     5378416                                                                              10100100001000101110000                                                                        3      11      -7                                     5391472                                                                              10100100100010001110000                                                                        3      11      -7                                     5423377                                                                              10100101100000100010001                                                                        3      15      -7                                     5506243                                                                              10101000000010011000011                                                                        3      15      -7                                     5534272                                                                              1010100011100100100000                                                                         3      11      -7                                     5542336                                                                              1010100100100011100000                                                                         3      11      -7                                     5580775                                                                              10101010010011111100111                                                                        3      15      5                                      5855487                                                                              10110010101100011111111                                                                        3      15      7                                      5959416                                                                              10110101110111011111000                                                                        3      11      7                                      6102774                                                                              10111010001111011110110                                                                        3      11      7                                      6393877                                                                              11000011001000000010101                                                                        3      15      -7                                     6482184                                                                              11000101110100100001000                                                                        3      11      -5                                     6863838                                                                              11010001011101111011110                                                                        3      11      7                                      7016379                                                                              11010110000111110111011                                                                        3      11      7                                      7043259                                                                              11010110111100010111011                                                                        3      11      7                                      7179951                                                                              11011011000111010101111                                                                        3      15      7                                      7207566                                                                              11011011111101010001110                                                                        3      15      7                                      7228335                                                                              11011100100101110101111                                                                        3      11      7                                      7245675                                                                              11011101000111101101011                                                                        3      11      7                                      7269135                                                                              11011101110101100001111                                                                        3      15      7                                      7272555                                                                              11011101111100001101011                                                                        3      11      7                                      7305402                                                                              11011110111100010111010                                                                        3      11      7                                      7305774                                                                              11011110111101000101110                                                                        3      11      7                                      7357522                                                                              11100000100010001010010                                                                        3      11      -7                                     7598677                                                                              11100111111001001010101                                                                        3      15      5                                      7844956                                                                              11101111011010001011100                                                                        3      11      5                                      7891899                                                                              11110000110101110111011                                                                        3      15      7                                      7912410                                                                              11110001011101111011010                                                                        3      11      7                                      7925466                                                                              11110001110111011011010                                                                        3      11      7                                      8042715                                                                              11110101011100011011011                                                                        3      15      7                                      8055099                                                                              11110101110100100111011                                                                        3      11      7                                      8116410                                                                              11110111101100010111010                                                                        3      15      7                                      8116782                                                                              11110111101101000101110                                                                        3      11      7                                      8272746                                                                              11111100011101101101010                                                                        3      11      7                                      8302185                                                                              11111101010111001101001                                                                        3      15      7                                      8313066                                                                              11111101101100011101010                                                                        3      11      7                                      8359245                                                                              11111111000110101001101                                                                        3      15      7                                      ______________________________________                                    

                  TABLE 7                                                         ______________________________________                                        (n = 25)                                                                                                max.                                                                          corr.  max. corr.                                                             (for-  (back- dc                                    number  bj                ward)  ward)  level                                 ______________________________________                                        381638  0000001011101001011000110                                                                       3      11     -5                                    446005  0000001101100111000110101                                                                       3      13     -3                                    465770  0000001110001101101101010                                                                       3      13     -3                                    473782  000000111001110101011010                                                                        3      13     -1                                    897941  0000011011011001110010101                                                                       3      13     -1                                    947565  0000011100111010101101101                                                                       3      15     1                                     2054758 000011111010110100110010                                                                        3      13     1                                     2054886 0000111110101101011100110                                                                       3      11     3                                     3275446 000110001111110101011010                                                                        3      17     3                                     3672501 0001110000000100110110101                                                                       3      15     -5                                    3672793 0001110000000101011011001                                                                       3      13     -5                                    4808590 0010010010101111110001110                                                                       3      15     1                                     4945678 0010010110111011100001110                                                                       3      13     1                                     6550893 0011000111111010101101101                                                                       3      13     5                                     6561626 0011001000001111101011010                                                                       3      11     -1                                    6692698 0011001100001111101011010                                                                       3      13     1                                     7093738 0011011000011110111101010                                                                       3      11     3                                     7345002 0011100000001001101101010                                                                       3      13     -5                                    7345586 0011100000001010101101010                                                                       3      17     -5                                    9609331 0100100101010000001110011                                                                       3      13     -5                                    9610015 0100100101010001100011111                                                                       3      15     -1                                    10178588                                                                              0100110110101000000011100                                                                       3      17     -5                                    10805191                                                                              0101001001101111111000111                                                                       3      15     5                                     10950975                                                                              0101001110001100100111111                                                                       3      13     3                                     11297951                                                                              0101011000110010010011111                                                                       3      13     1                                     11374620                                                                              0101011011001000000011100                                                                       3      13     -5                                    11383232                                                                              0101011011011000111000000                                                                       3      13     -3                                    11499628                                                                              0101011110111100001101100                                                                       3      11     3                                     11923532                                                                              0101101011111000001001100                                                                       3      11     -1                                    11923660                                                                              0101101011111000011001100                                                                       3      13     1                                     13014848                                                                              0110001101001011101000000                                                                       3      11     -5                                    13197255                                                                              0110010010101111111000111                                                                       3      13     5                                     13415920                                                                              0110011001011010111110000                                                                       3      13     1                                     13546992                                                                              0110011101011010111110000                                                                       3      11     3                                     14334400                                                                              0110110101011100111000000                                                                       3      13     -1                                    14335768                                                                              0110110101011111100011000                                                                       3      17     3                                     14802340                                                                              0111000011101110110100100                                                                       3      13     1                                     14939428                                                                              0111000111111010100100100                                                                       3      15     1                                     18615003                                                                              1000111000000101011011011                                                                       3      15     -1                                    18752091                                                                              1000111100010001001011011                                                                       3      13     -1                                    19218663                                                                              1001001010100000011100111                                                                       3      17     -3                                    19220031                                                                              1001001010100011000111111                                                                       3      13     1                                     20007439                                                                              1001100010100101000001111                                                                       3      11     -3                                    2013851 1001100110100101000001111                                                                       3      13     -1                                    20357176                                                                              1001101101010000000111000                                                                       3      13     -5                                    20539583                                                                              1001110010110100010111111                                                                       3      11     5                                     21630771                                                                              1010010100000111100110011                                                                       3      13     -1                                    21630899                                                                              1010010100000111110110011                                                                       3      11     1                                     22054803                                                                              1010100001000011110010011                                                                       3      11     -3                                    22171199                                                                              1010100100100111000111111                                                                       3      13     3                                     22179811                                                                              1010100100110111111100011                                                                       3      13     5                                     22256480                                                                              1010100111001101101100000                                                                       3      13     -1                                    22603456                                                                              1010110001110011011000000                                                                       3      13     -3                                    22749240                                                                              1010110110010000000111000                                                                       3      15     -5                                    23375843                                                                              1011001001010111111100011                                                                       3      17     5                                     23944416                                                                              1011011010101110011100000                                                                       3      15     1                                     23945100                                                                              1011011010101111110001100                                                                       3      13     5                                     26208845                                                                              1100011111110101001001101                                                                       3      17     5                                     26209429                                                                              1100011111110110010010101                                                                       3      13     5                                     26460693                                                                              1100100111100001000010101                                                                       3      11     -3                                    26861733                                                                              1100110011110000010100101                                                                       3      13     -1                                    26992805                                                                              1100110111110000010100101                                                                       3      11     1                                     27003538                                                                              1100111000000101010010010                                                                       3      13     -5                                    28608753                                                                              1101101001000100011110001                                                                       3      13     -1                                    28745841                                                                              110110110101000001110001                                                                        3      15     -1                                    29881638                                                                              1110001111111010100100110                                                                       3      13     5                                     29881930                                                                              1110001111111011001001010                                                                       3      15     5                                     30278985                                                                              1110011100000010101001001                                                                       3      17     -3                                    31499545                                                                              1111000001010010100011001                                                                       3      11     -3                                    31499673                                                                              1111000001010010110011001                                                                       3      13     -1                                    32606866                                                                              1111100011000101010010010                                                                       3      15     -1                                    32656490                                                                              1111100100100110001101010                                                                       3      13     1                                     33080649                                                                              1111110001100010101001001                                                                       3      13     1                                     33088661                                                                              1111110001110010010010101                                                                       3      13     3                                     33108426                                                                              1111110010011000111001010                                                                       3      13     3                                     33172793                                                                              1111110100010110100111001                                                                       3      11     5                                     ______________________________________                                    

                  TABLE 8                                                         ______________________________________                                        (n = 27)                                                                                                max.                                                                          corr.  max. corr.                                                             (for-  (back- dc                                    number bj                 ward)  ward)  level                                 ______________________________________                                        930410 000000011100011001001101010                                                                      3      15     -7                                    1624362                                                                              000000110001100100100101010                                                                      3      15     -9                                    1860757                                                                              000000111000110010010010101                                                                      3      15     -7                                    15798573                                                                             000111100010001000100101101                                                                      3      11     -5                                    39566215                                                                             010010110111011101110000111                                                                      3      11     5                                     44341440                                                                             010101001001001100011000000                                                                      3      15     -9                                    45245312                                                                             010101100100110001110000000                                                                      3      15     -7                                    45534783                                                                             010101101101100111000111111                                                                      3      15     7                                     ______________________________________                                    

                  TABLE 9                                                         ______________________________________                                        (n = 29)                                                                                                 max.   max.                                                                   corr.  corr.                                                                  (for-  (back-                                                                              dc                                    number bj                  ward)  ward) level                                 ______________________________________                                        11687143                                                                             00000101100100101010011100111                                                                     3      15    -3                                    20815162                                                                             00001001111011001110100111010                                                                     3      15    1                                     29650650                                                                             00001110001000110111011011010                                                                     3      17    -1                                    52082271                                                                             00011000110101011011001011111                                                                     3      15    3                                     52401586                                                                             00011000111111100101011011010                                                                     3      15    1                                     52417970                                                                             00011000011111101010110110010                                                                     3      11    3                                     69590574                                                                             00100001001011101111000101110                                                                     3      13    1                                     70752046                                                                             00100001101111001011100101110                                                                     3      19    1                                     79132430                                                                             00100101101110111011100001110                                                                     3      15    3                                     162536693                                                                            01001101100000001110011110101                                                                     3      15    -1                                    162873112                                                                            01001101101010011111100011000                                                                     3      15    1                                     162889496                                                                            01001101101010111111100011000                                                                     3      11    3                                     169410125                                                                            01010000110001111111001001101                                                                     3      15    1                                     191808624                                                                            01011011011101100010001110000                                                                     3      17    -1                                    494459536                                                                            01011100101110011011110010000                                                                     3      15    1                                     236838308                                                                            01110000111011101110110100100                                                                     3      15    3                                     244282500                                                                            01110100011110111010010000100                                                                     3      19    -1                                    245185924                                                                            01110100111010011110110000100                                                                     3      19    1                                     ______________________________________                                    

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a system block diagram of a spread spectrum communicationdevice showing a first application example of the present invention;

FIG. 2 is a diagram illustrating a signal code sequence;

FIG. 3 is a system block diagram of a part of a communication deviceshowing a second application example of the present invention;

FIG. 4 shows a surface acoustic wave device using a second applicationexample of the present invention;

FIG. 5 is a system block diagram of a spread spectrum communicationdevice showing a third application example of the present invention;

FIG. 6 shows a code sequence used in the third application example ofthe present invention;

FIG. 7 shows a matched signal used in the third application example ofthe present invention;

FIG. 8 shows the frequency response of a matched filter used in thethird application example of the present invention;

FIG. 9 shows a conventional Barker code (13 chips);

FIG. 10 shows a matched signal in the case where the conventional Barkercode (13 chips) is used;

FIG. 11 shows the frequency response of a matched filter in the casewhere the conventional Barker code (13 chips) is used;

FIG. 12 shows tap coefficients of a matched filter using a fourthapplication example of the present invention;

FIG. 13 shows a matched signal used in the fourth application example ofthe present invention;

FIG. 14 shows tap coefficients of a matched filter using a fifthapplication example of the present invention;

FIG. 15 shows a matched signal used in the fifth application example ofthe present invention;

FIG. 16 is a system block diagram of a spread spectrum communicationdevice showing a sixth application example of the present invention;

FIG. 17 is a system block diagram of a part of a communication deviceshowing a seventh application example of the present invention;

FIG. 18 is a system block diagram of a part of a communication deviceshowing an eighth application example of the present invention;

FIG. 19 is a system block diagram of a part of a communication deviceshowing a ninth application example of the present invention;

FIG. 20 is a system block diagram of a part of a communication deviceshowing a tenth application example of the present invention;

FIG. 21 is a system block diagram of a part of a communication deviceshowing an eleventh application example of the present invention; and

FIG. 22 shows a communication system using a device shown in a twelfthapplication example of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereafter, modes for carrying out the present invention will bedescribed by referring to FIGS. 1 through 23.

However, some modes hereafter described are shown in order to explainapplication examples for carrying out the present invention. Modes forcarrying out the present invention are never limited to applicationexamples described here.

FIG. 1 is a diagram schematically showing a spread spectrumcommunication device to which the present invention has been applied. Aninformation signal is inputted from an input terminal 1, multiplied in amixer 2 by a signal supplied from a pseudo noise code generator 3,furthermore multiplied in a mixer 4 by a carrier supplied from anoscillator 5, amplified in an amplifier 6, and outputted from an antenna7. Here, a code shown in TABLES 1 through 9 was used as the pseudo noisecode.

In a receiving system, a signal inputted from the antenna 7 is amplifiedin an amplifier 8, demodulated, converted to a digital signal in asquare wave output circuit 9, and taken out from an output terminal 10as an information signal. Here, a code similar to the above describedcode was used as a reference code for demodulating the information. (Itcoincides with the pseudo noise code of the transmitter.) FIG. 2 is adiagram showing a signal code sequence. In the case of the synchronousdetection system, a signal code sequence Sk corresponds to 1 and 0 ofthe information code, and it is represented as ##EQU1## where mj (j=1,2, . . . , n; n=code length) corresponds to a pseudo noise code bj shownin TABLES 1 through 9, and it is represented by the following equation.##EQU2## In the same way, in the case of the delay detection system, thesignal code sequence Sk is represented by the following equation.##EQU3## Denoting a reference code of the receiving side by Mj, acorrelation coefficient Ok is represented by the following equation.##EQU4## In the case where Mj=mj, the correlation coefficient Okrepresents an auto-correlation coefficient and it is represented by thefollowing equation. ##EQU5## Sub-peaks other than correlation peaks(mod(k/n)≠1) are referred to as side lobes. As this value becomessmaller, the error rate of the receiver is typically reduced. For thecase where the code length is at least 14, such a code that the sidelobe value calculated by using the Expression 5 is 3 or less is shown inTABLES 1 through 9. Calculation conducted here corresponds to allarrangements (0, 0), (0, 1), (1, 0) and (1, 1) of 0 and 1 of theinformation code. (The above described 0 and 1 of the information codeindicate that they are mutually in the relation of inverted code.)Calculation was conducted as to such an arrangement of Sk that signswhereby mj is multiplied are (+, +, -). That is, calculating toExpression 5 above is performed on a single code sequence S_(k) whichincludes M_(js) have signs (+, +, -), respectively (i.e., S_(k) =+M_(j),+M_(j), -M_(j)). (In the remaining case where the signs are (-, -, +), aresult equal in absolute value and opposite in sign to the abovedescribed result is obtained. In other words, only the polarity isdifferent. Therefore, the above described calculation alone suffices.)

In TABLES 1 through 9, "bj" is a derived code sequence, and "number" isa value obtained by regarding the "bj" as a binary number and convertingit to a decimal number. Furthermore, "max corr. (forward)" is a sidelobe value, and "max corr. (backward)" is a maximum value of correlationvalue obtained in the case where codes are reversed bilaterally.Furthermore, "dc level" is the sum total of n "mj"s. As a matter ofcourse, similar results are obtained even if code inversion (1<=>0) isconducted on these codes. Since it takes an enormous time to conductcalculations, inverted codes are omitted for lengthy code lengths. Ifthese codes are used as the pseudo noise code, there is obtained aspread spectrum communication device having a processing gain of atleast 14 in auto-correlation side lobe, having smaller time-axis sidelobes of received matched signal, having a smaller error rate, andhaving favorable characteristics.

A second application example of the present invention will now bedescribed by referring to FIG. 3. The same components as those in FIG. 1showing the first application example are denoted by like numerals. FIG.3 is a diagram showing a receiving part of the second applicationexample of the present invention. A received signal taken in from anantenna 7 is amplified in an amplifier 8, converted to a matched signalin a matched filter 11, detected in a detector circuit 12, demodulated,converted to a digital signal by a square wave output circuit 13, andoutputted from an output terminal 10. In the present applicationexample, a matched filter is used as a demodulating element. Thisresults in a feature that the circuit can be simply formed.

A third application example of the present invention will now bedescribed by referring to FIGS. 4 and 5.

FIG. 4 is a diagram schematically showing a SAW (surface acoustic wave)matched filter 18. On a SAW substrate 14, an input interdigitalelectrode set 15 and an output interdigital electrode set 16 aredisposed. Furthermore, in order to suppress a reflected wave coming froma substrate face, a sound absorbing material 17 is coated. The inputinterdigital electrode set 15 has such a structure that the electrodepolarity is inverted every electrode. (The electric polarity differsdepending upon whether the electrode is connected to an upper commonelectrode or a lower common electrode.) The output interdigitalelectrode set 16 has a matched filter structure in which the electrodepolarity is inverted in association with the pseudo noise code. As thesubstrate 14, an ST-cut crystal substrate is used in order to preventthe center frequency from being shifted due to the temperature.

FIG. 5 is a system block diagram of the present application example. Thesame components as those in FIG. 1 showing the first application exampleare denoted by like numerals. A received signal taken in from an antenna7 is amplified in an amplifier 8, converted to a matched signal in a SAWmatched filter 18 of the present application example, multiplied in amixer 20 by a signal preceding it by one information bit and delayed ina SAW delay line 19 and thus detected, converted in a square wave outputcircuit 13 to a digital signal, and outputted from an output terminal10. In the present application example, delay detection is conducted byusing an SAW element. This results in a feature that the detectorcircuit can be formed more simply.

FIG. 6 is a diagram showing mj corresponding to a 25-chip code bj ofnumber (num) 947565 shown in TABLE 7.

FIG. 7 is a diagram showing a matched signal waveform in the case wherethis mj code is used on the transmitting side and the reference code ofthe matched filter on the receiving side is made the same. The carrierfrequency is 300 MHz, and the information rate is 1 Mbps. At this time,a favorable side lobe suppression factor (peak to side lobe ratioD/U=18.2 dB) is obtained.

FIG. 8 is a diagram showing the frequency response of the matched filterof the present application example. In FIG. 8, ripples on the frequencyresponse correspond to side lobe deterioration. For the purpose ofcomparison, the case where the conventional 13-chip Barker code is usedwill now be also described.

FIG. 9 is a diagram showing mj corresponding to this Barker code.

FIG. 10 is a diagram showing the matched signal waveform in the casewhere this mj code is used on the transmitting side and the referencecode of the matched filter on the receiving side is made the same.

In the same way as the present application example, the carrierfrequency was set equal to 300 MHz and the information rate was setequal to 1 Mbps. A side lobe suppression factor (peak to side lobe ratioD/U=22.1 dB) was obtained.

FIG. 11 is a diagram showing the frequency response of the matchedfilter in the case where the Barker code is used. It is shown thatripples are comparatively small and the side lobe suppression factor islarge.

As described above, use of the present application example makes itpossible to obtain a communication device having a chip length of 25 andimprove significantly the processing gain at the sacrifice of only aslight side lobe deterioration as compared with the case where theconventional Barker code is used.

A fourth application example of the present invention will now bedescribed by referring to FIGS. 12 and 13. In the above described thirdapplication example, the side lobe suppression factor was D/U=18.2 dB.In the present application example, however, further side lobesuppression is conducted.

FIG. 12 is a diagram showing a reference 25-chip tap coefficient Mj ofthe receiving side in the present application example. In order toconduct side lobe suppression of the matched signal, respective taps areprovided with weights.

FIG. 13 shows a matched signal waveform in the case where the mj code ofthe third application example are used on the transmitting side andrespective taps of the matched filter of the receiving side are providedwith weights corresponding to the above described reference code Mj.Coefficients of FIG. 12 were derived by using an optimization algorithm.The carrier frequency is 300 MHz, and the information rate is 1 Mbps. Bydoing so, a favorable side lobe suppression factor (peak to side loberatio D/U=19.8 dB) as compared with the third application example isobtained without increasing the number of taps of the receiving side.

A fifth application example of the present invention will now bedescribed by referring to FIGS. 14 and 15. In the fourth applicationexample, the number of taps was set equal to 25 equally for both thetransmitting side and the receiving side. In the present applicationexample, however, the number of taps on the receiving side was set equalto 49 in order to conduct further side lobe suppression.

FIG. 14 is a diagram showing the reference 49-chip tap coefficient Mj onthe receiving side of the present application example. For matchedsignal side lobe suppression, respective taps are provided with weights.

FIG. 15 is a diagram showing a matched signal waveform in the case wherethe mj code of the third application example is used on the transmittingside and respective taps of the matched filter on the receiving side areprovided with weights corresponding to the above described referencecode Mj. Coefficients of FIG. 14 were derived by using the optimizationalgorithm. The carrier frequency is 300 MHz, and the information rate is1 Mbps. As compared with the conventional case where the Barker code isused, a favorable side lobe suppression factor (peak to side lobe ratioD/U=24.4 dB) is obtained.

A sixth application example of the present invention will now bedescribed by referring to FIG. 16. The same components as those in FIG.5 showing the third application example are denoted by like numerals. Inthe third application example, demodulation is conducted directly in thetransmission signal band. Since the frequency is high, however, signalprocessing is difficult in some cases. In the present applicationexample, the frequency is lowered by multiplication with a signal with asignal generated by an oscillator 22 conducted in a mixer 21 andthereafter demodulation processing is conducted. If the presentapplication example is used, demodulation processing with acomparatively low frequency band is possible, resulting in a feature ofeasy circuit design.

A seventh application example of the present invention will now bedescribed by referring to FIG. 17.

FIG. 17 is a diagram showing a receiving part of a communication devicein the seventh application example. The same components as those in FIG.3 showing the second application example are denoted by like numerals.In the second application example, demodulation is conducted by using amatched filter. In the case where the information rate is slow, however,the device size of the matched filter becomes large. In the presentapplication example, an signal outputted from a pseudo noise codegenerator 23 is multiplied in a mixer 24 by a carrier signal of anoscillator 25 having the same frequency as that of the carrier, and aresultant signal is synchronized with the received signal and it ismultiplied in a mixer 26 by the received signal. As a result, ademodulated signal can be obtained. The present application example hasa feature that signal demodulation can be conducted without increasingthe device size even in the case where the information rate iscomparatively slow.

An eighth application example of the present invention will now bedescribed by referring to FIG. 18.

FIG. 18 is a diagram showing a receiving part of a communication devicein the eighth application example. The same components as those in FIG.3 showing the second application example are denoted by like numerals.In the seventh application example, a pseudo noise signal is generatedto conduct demodulation. On the receiver side as well, however, a signalgenerator is needed, resulting in a large circuit scale. In the presentapplication example, a carrier frequency oscillator 28 is multiplied ina mixer 27 by the received signal. Furthermore, a resultant signal isconverted to a digital signal by a detector circuit 29 and a square waveoutput circuit 30. In a digital correlation signal processing circuit31, the digital signal is subjected to processing according to theequation of the Expression 4 and the equation of the Expression 5. Inthe present application example, correlation demodulation processing canbe conducted by using digital processing. This results in a feature thatthe device can be fabricated at comparatively low cost in the case wherethe information rate is comparatively slow, or the pseudo noise codelength is short.

A ninth application example of the present invention will now bedescribed by referring to FIG. 19.

FIG. 19 is a diagram showing a receiving part of a communication devicein the ninth application example. The same components as those in FIG.17 showing the seventh application example are denoted by like numerals.In the eighth application example, demodulation is conducted in thedigital circuit. In the case where the information rate is fast and thepseudo noise code length is long, processing cannot be conducted in somecases because the clock frequency of the digital circuit is low. In thepresent application example, a signal outputted from a pseudo noise codegenerator 23 is multiplied in a mixer 24 by a carrier signal of anoscillator 25 having the same frequency as the carrier. A resultantsignal and the received signal are subjected to convolution integralprocessing in a convolver 32 which is a correlation element.Furthermore, a resultant signal is subjected to demodulation in adetector circuit 33. The present application example has a feature thatthe demodulated signal can be obtained comparatively easily so long asthe carrier frequency can be synchronized with the pseudo noise codecycle even in the case where the information rate is fast and the pseudonoise code length is long.

As compared with the sixth through ninth application examples, the casewhere the matched filter is used as in the second and third applicationexamples has a feature that signal synchronizing is unnecessary becausethe code on the receiving side is fixed. On the contrary, the sixththrough ninth application examples have a feature that the referencecode on the receiving side can be changed freely so as to correspond tothe code on the transmitting side because the code is variable.

A tenth application example of the present invention will now bedescribed by referring to FIG. 20.

FIG. 20 is a diagram showing a detection part of a communication devicein the tenth application example. In the present application example, adelay detection system is used as the detection system, and demodulationis conducted by multiplying a current signal, in a mixer 35, by a signalpreceding a current signal by one information bit supplied from a delayline 34. In the present application example, the detector circuit can besimplified.

An eleventh application example of the present invention will now bedescribed by referring to FIG. 21.

FIG. 21 is a diagram showing a detection part of a communication deviceof the eleventh application example. In the present application example,a synchronous detection system is used as the detection system, anddemodulation is conducted by multiplying a clock reproduced by a clockdetection circuit 36, in a mixer 35, by a signal. In the presentapplication example, a better error rate than that of the delaydetection system is obtained.

A twelfth application example of the present invention will be nowdescribed by referring to FIG. 22.

FIG. 22 is a diagram showing a communication system of the twelfthapplication example. In the present application example, communicationdevices of the present system are used in a LAN. Present communicationdevices 41 and 42 are connected to a LAN cable 38. Present communicationdevices 40 and 43 are connected to terminals 39 and 44. Presentcommunication devices 46 and 47 are connected to terminals 45 and 48.Between terminals (without a wire system between), communication can beconducted freely. If the present application example is used, it is notnecessary to connect each terminal to a LAN cable, and consequentlyterminals can be freely moved.

INDUSTRIAL APPLICABILITY

According to the present invention, the side lobes of the correlationcoefficient can be suppressed with the pseudo noise code length of atleast 14 as heretofore described. Therefore, the error rate can bereduced and the processing gain can be improved in a spread spectrumcommunication device and a communication system using the spreadspectrum communication device.

What is claimed is:
 1. A spread spectrum communication device in adirect spreading communication device using a pseudo noise code invertedin polarity so as to correspond to digital information,wherein in saidspread spectrum communication device, as said pseudo noise code, apseudo noise code having a code length of at lease 14 and anauto-correlation side lobe of 3 or less is used, and wherein said pseudonoise code is one of the codes listed in Tables 1-9 and "0"s and "1"s ineach of the codes listed in Tables 1-19 are interchangeable with eachother.
 2. A surface acoustic wave device in which at least one set of atleast two sets of interdigital electrodes forms an input electrode setor an output electrode set and disposition is conducted so as tomutually invert electrode polarities,wherein an input signal inputted toan input electrode set is a signal subjected to spreading processingusing a pseudo noise code, said pseudo noise code has a code length ofat least 14, and a pseudo noise code having an auto-correlation sidelobe of 3 or less is employed, and wherein said pseudo noise code is oneof the codes listed in Tables 1-9 and "0"s and "1"s in each of the codeslisted in Tables 1-9 are interchangeable with each other.